EMS helicopter inadvertently penetrates rxxx, aided and assisted by directional gyro indication erro...

Attributes
ACN	155401
Time
Date	199008
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zzz
State Reference	US
Altitude	agl bound lower : 700 agl bound upper : 700
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz
Operator	common carrier : air taxi
Make Model Name	Helicopter
Flight Phase	cruise other
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 120 flight time total : 12000 flight time type : 1500
ASRS Report	155401
Person 2
Affiliation	company : air taxi
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : less severe non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : exited penetrated airspace
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On an EMS mission, I had departed the accident site and was taking the patient to hospital in xyz. The visibility in flight was 2-3 mi due to haze. That part of the country is nothing but woods. Flying the heading to take me up to ZZZ and then over to xyz, I noticed a familiar landmark. I checked the directional gyro with the medium large transport compass and saw that the directional gyro had precessed about 30 degrees, thus flying what I thought was the correct heading (as shown from the LORAN), it put me into rxxx. I immediately turned north, checking the magnetic compass, and proceeded to exit the restr area and continue to the hospital with the patient. As I flew along I checked and saw that the slaved, free toggle switch was in the free position. I feel that on final approach to the accident site, my paramedic hit the slave-free switch by mistake, thus allowing the directional gyro to precess. On this helicopter, the intercom-transmit switch (which is a toggle switch also) is about 2' above the slave-free switch. I think that on final he must have hit the slave-free switch when he went to transmit that we were landing to our dispatcher at the hospital.

Original NASA ASRS Text

Title: EMS HELICOPTER INADVERTENTLY PENETRATES RXXX, AIDED AND ASSISTED BY DIRECTIONAL GYRO INDICATION ERROR.

Narrative: ON AN EMS MISSION, I HAD DEPARTED THE ACCIDENT SITE AND WAS TAKING THE PATIENT TO HOSPITAL IN XYZ. THE VISIBILITY IN FLT WAS 2-3 MI DUE TO HAZE. THAT PART OF THE COUNTRY IS NOTHING BUT WOODS. FLYING THE HDG TO TAKE ME UP TO ZZZ AND THEN OVER TO XYZ, I NOTICED A FAMILIAR LANDMARK. I CHKED THE DIRECTIONAL GYRO WITH THE MLG COMPASS AND SAW THAT THE DIRECTIONAL GYRO HAD PRECESSED ABOUT 30 DEGS, THUS FLYING WHAT I THOUGHT WAS THE CORRECT HDG (AS SHOWN FROM THE LORAN), IT PUT ME INTO RXXX. I IMMEDIATELY TURNED N, CHKING THE MAGNETIC COMPASS, AND PROCEEDED TO EXIT THE RESTR AREA AND CONTINUE TO THE HOSPITAL WITH THE PATIENT. AS I FLEW ALONG I CHKED AND SAW THAT THE SLAVED, FREE TOGGLE SWITCH WAS IN THE FREE POS. I FEEL THAT ON FINAL APCH TO THE ACCIDENT SITE, MY PARAMEDIC HIT THE SLAVE-FREE SWITCH BY MISTAKE, THUS ALLOWING THE DIRECTIONAL GYRO TO PRECESS. ON THIS HELI, THE INTERCOM-XMIT SWITCH (WHICH IS A TOGGLE SWITCH ALSO) IS ABOUT 2' ABOVE THE SLAVE-FREE SWITCH. I THINK THAT ON FINAL HE MUST HAVE HIT THE SLAVE-FREE SWITCH WHEN HE WENT TO XMIT THAT WE WERE LNDG TO OUR DISPATCHER AT THE HOSPITAL.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

EMS helicopter inadvertently penetrates rxxx, aided and assisted by directional gyro indication error.